Apparatus for making filament tobacco smoke filters



May 16, 1967 P. GALLAGHER 3,

APPARATUS FOR MAKING FIL-AMENT TOBACCO SMOKE FILTERS Original Filed Aug.31, 1961 PAUL GALLAGHER INV TOR.

QMWMTLu A TTOR/VEYS United States Patent 3,320,110 APPARATUS FOR MAKINGFILAMENT TOBACCO SMOKE FILTERS Paul Gallagher, Kingsport, Tenn, assignorto Eastman Kodak Company, Rochester, N.Y., a corporation of New JerseyContinuation of application Ser. No. 135,245, Aug. 31, 1961. Thisapplication Aug. 1, 1966, Ser. No. 570,133 5 Claims. (Cl. 156-438) Thisapplication is a continuation of my copending application Ser. No.856,769, filed Dec. 2, 1959, and now US. Patent No. 3,205,107.

This invention relates to apparatus for the manufacture of filamenttobacco smoke filters. More particularly this invention relates toapparatus for the manufacture of cellulose acetate paper-wrapped filterswhich filters are improved in that the filaments of the filter arebonded to the wrapping material enclosing the periphery of the filter.

The manufacture of cellulose acetate tobacco smoke filters in accordancewith the disclosure contained in my co-workers US. Patent No. 2,794,480has been favorably received in the industry and good filters may beproduced by the disclosure of said patent. However, in some instances,such as the making of filters from filament material of low denierand/or low crimp, there may be a tendency of the filament part of thefilter not to be as firmly positioned against the wrapper enclosing thefilter as is desirable. This can permit the channeling or by-passing ofthe smoke between the filaments and the wrapper, thereby reducing theefiiciency of the filter. In a co-pending US. patent application ofanother of my co-workers, Ser. No. 824,577, now US. Patent 3,025,861,the aforementioned problem concerning the separation of the filamentsfrom the wrapper is discussed in detail, and my co-worker has describedprocedure for overcoming this difiiculty. It is apparent that in themanufacture of filters of the type indicated that it is important to beable to operate at high rates of production. Accordingly, thedevelopment of certain improvements in the apparatus for making filtersas described in my co-workers patent and application referred to aboverepresents a desirable result.

After extended investigation, I have found an apparatus whereby improvedfilament filters may be produced at relatively high speeds of productionto give filter elements generally in accordance with the product of saidapplication 824,577, which filter products are characterized in that thefilaments and the inside of the wrapper are not subject to separation orthe like. In addition, such filters may possess other advantages, forexample, such as having greater firmness.

This invention has for one object to provide apparatus for use toimprove the efficiency of tobacco smoke filters made from crimpedcontinuous filaments by eliminating the possibility that smoke may passbetween the periphery of the filter and the wrapper. Another object isto provide apparatus for the manufacture of filters resistant toshrinking in cross section due to the action of the hot, moist smoke. Afurther object is to provide a simple, inexpensive apparatus forobtaining adhesion between the wrapper and the periphery filaments ofthe filter bundle. Another object is to provide means readily adaptableto existing filter forming equipment and suited to high speed operation.Still another object is to furnish apparatus for securing a uniformsquare cut when subdividing filters into short lengths, said cut beingessentially free of any fuzziness caused by displacement of the fibersadjacent to the inner surface of the wrap.

In the broader aspects, my invention involves apparatus for coating aplug (filament-filter) wrap paper or other wrapper with a coatingcomposition by means of which the outer layer of filaments in the filterelements are made to adhere to the wrapping material. By thus fixing theposition of the filaments at the periphery of the filter, the shrinkageassociated with smoking, particularly with fine denier per filamenttows, is eliminated. As a result, substantially all of the smoke mustpass through the filter between the filaments, and the tar removal isincreased and more consistent.

Any one of several general types of adhesives may be applied using theapparatus of this invention: 1) a molten thermoplastic material, (2) acompound which is sensitive to the solvent action of a plasticizercomponent thereof, and (3) a water-soluble adhesive. Thermoplasticadhesives which may be used include polyethylene, polypropylene,polyvinyl acetate, copolymers of various acrylates and methacrylates,ethyl cellulose derivatives, various resins of the terpene family, andother thermoplastic materials known to those skilled in the art. If aplasticizer-sensitive coating composition is used a preferablecomposition is a cellulose ester-triacetin liquid dope which compositionpreferably contains l4% cellulose acetate, balance triacetin. However,higher percentages of cellulose acetate may be used. When theplasticizer-sensitive composition contains less than 10% celluloseester, conventional paste wheel and sealer are ordinarily used, one edgeof the wrapper being left uncoated for a sealer composition to be addedby the paste wheel to the overlapping seal portion. In the case of acellulose ester-triacetin coating composition, the composition is not anadhesive at the time of application from the applicator, but, on theother hand, when it contacts the filaments during the wrappingoperation, it quite readily bonds the filaments to the paper, apparentlyby absorption of the triacetin. In place of triacetin (glyceroltriacetate) any of the following compounds may be used in thepasticizer-sensitive compounds: glycerol tripropionate, di(methoxyethyl)phthalate, triethyl citrate and methyl phthalyl ethyl glycolate. Thesolid component which must be soluble in the plasticizer may becellulose acetate propionate, polyvinyl acetate, certain natural gums orthe like. When the paper is coated with a watersoluble adhesive, theadhesive may be activated by the application of water by a sponge orwicking device just before the paper enters the garniture. Thewater-sensitive adhesive may be an animal glue adhesive or a starchpaste adhesive, or the like.

In accordance with one embodiment of the present invention, the coatingcomposition was applied through a A" OD. tube terminating in a flaredslot x The paper passed under and was in contact with the slot. Thisspreader tube was connected to a dope supply tank which wasapproximately 2 feet above the surface of the slot in the spreader. Theflow of dope of coating composition or the weight of dope deposited onthe paper was controlled by the dimensions of the slot, the viscosity ofthe dope, the height of the supply tank and the pressure of the paperagainst the slot. When the coating composition is highly viscous, forinstance contains more than 10% cellulose acetate if aplasticiZer-sensitive composition is used or when the coatingcomposition is a thermoplastic compound such as molten polyethylene, aroller applicator may be used to replace the slot applicator to bedescribed in detail hereinafter. Using the above described equipment andmethod, it was found that 1 g. to 1.5 g. of dope per cm. length of paper[equivalent to 23 g. to 34.5 g./m. (grams per square meter) of coatedarea] could be applied evenly and gave good adhesion between the filterand the paper wrap. The coating composition may be applied over the fullwidth of the paper, on only a narrow center portion which is to bediametrically opposite the seal after preparation of the filter, or

:3 over substantially the entire width of the paper with the exceptionof a small area on one edge, depending upon the degree of adherence ofthe paper to the filaments desired and whether it is desired tosubsequently add a sealing glue on the overlapping seam portion.

In further detail, the over-all apparatus for making filters inaccordance with the present invention may be along the lines disclosedin the aforementioned US. Patent 2,794,480. That is, apparatusarrangement for moving from the package the filaments which are to bemade into the filter, the opening and handing of these filaments, thespraying of these filaments and the like may be in accordance with thedisclosure of FIG. 1 of said Patent 2,794,480. However, referring toFIG. of said patent, in order to practice the present invention, theapparatus for processing of the paper wrap and certain other items wouldbe changed to embody the present invention.

Or, rather than proceeding with the arrangement disclosed in FIG. 5 justmentioned, the filter forming and wrapping means described in copendingUS. patent application Ser. No. 761,602, now US. Patent 3,016,945, of myco-worker Wexler may be employed.

For assistance in the better understanding of the instant invention,reference is made to the attached drawing forming a part of the presentapplication. In the attached drawing:

FIG. 1 is a semidiagrammatic side elevation view of one apparatusarrangement which would be used for carrying out the present invention;

FIG. 2 is a detail view on an enlarged scale of a portion of theapparatus shown in FIG. 1; and

FIG. 3 is a detail top view of one form of coating applicator forapplying the coating of the instant invention.

Referring to FIG. 1, which concerns a segment of an apparatus used forthe line production of filters, it will be kept in mind that thefilaments 14 shown in FIG. 1 have gone through other steps of theprocess (not shown) so that the filaments are at the stage of theprocess where they are to be wrapped. In further detail, the filamentswhich are being made into a filter have proceeded through the firststeps of the aforementioned Patent 2,794,480 such as indicated in FIGS.1, 2 and 3 of said Patent 2,794,480 and have now arrived at the wrappingstage indicated in FIG. 5 of said Patent 2,794,480.

Or, the filaments may have been processed according to apparatusdescribed in said Wexler application Ser. No. 761,602, now U.S. Patent3,016,945, and be at the Wrapping stage shown in this application.

Therefore, referring to FIG. 1, a source of paper wrap material isprovided at 2, such wrapping material being continuously supplied from aroll. This wrap material is passed under a guide roll 3 so that it maybe directed in contact with the applicator 4 of the present inventionafter the paper wrap passes over roll 10. The wrap used in the presentinvention may be conventional filter wrap paper of a thickness ofapproximately 0.03 mm. However, in many instances where the filamentsbeing processed are of a denier of 3 or below, I prefer to use a wrap ofa greater thickness such as 0.06 mm.

The applicator 4 is positioned (as better shown in FIG. 2) to applycertain coatings in accordance with the present invention against theinside of the paper wrap after the wrap passes over roll 10. It is moreor less cylindrical or of cylindrical portions with the exception of atapered nozzle portion, which flattens out and expands somewhat as ittouches the moving paper 11 substantially perpendicularly. Theapplicator 4 is connected by flexible conduits 6 through a valve means 7which is connected to supply tank 8. The control of the height (head) ofthis supply tank above the applicator and the level therein are of someimportance in obtaining the most uniform coating out of applicator 4.

Therefore, by the combination of applicator 4 with the paper passingover roll 10 there may be applied to the inside of the paper arelatively thin layer of the coating composition of the presentinvention. This may be accomplished at relatively high speed since thecoating composition of the present invention is not adhesive orparticularly tacky at the point of application thereof. As will be notedfrom the description hereinafter, the coating composition applied withapparatus of the present invention does produce bonding between thefilaments and the paper wrap.

This coated wrap 11 is then fed into the filter forming garniture 12.This garniture 12 is provided with suitable means 13 through which thefilaments may be injected into the garniture for forming into thedesired filter shape.

The formed filter 16 leaving garniture 12 is wrapped in the wrapper.Pasting and sealing means designated generally at 17 and 18 may beprovided for sealing the filter. Also, means may be provided for heatingthe sealed filter element, cutting the filter elements into certainlengths and the like. The bar portion 19 of sealer 18 may be heated insuch a manner as to transfer heat to the moving band and onto the seamportion of the filter product. Since these various parts may be inaccordance with the disclosure in the aforesaid Patent 2,794,480 or asdisclosed in said companion application 761,602, now US. Patent3,016,945, extended description thereof appears to be unnecessary. It issufficient to indicate that the formed and Wrapped filter is ejected at20 and may be stored, packaged or otherwise handled in the conventionaland desired manner.

Referring now to FIG. 2, which figure shows on a larger scale thefeature of applying the coatings of the present invention, the tip ofthe applicator is indicated at 21, which tip slightly depresses thepaper after it passes in contact with roll 25. The paper is coated onthe inside as indicated at 23. The applicator is positioned in a mannerso that it may be rotated as at 22 for better applying the coating andcontrolling the thickness of the coating as will be apparent from thedescription hereinafter.

Referring to FIG. 3, the simple internal construction of the applicatoris disclosed. It will be noted that the upper end of the applicator 26is of a size and shape to permit the fastening thereof to the flexibleconduit 6 of FIG. 1. The applicator increases in size as at 27. At theoutlet end 21, the applicator while increasing in width, tapers to aslot orifice. The width of this slot may be slightly less than the widthof the paper when it is desired to leave a slight uncoated margin forsealing purposes or considerably less when it is desired to apply thecoating composition only in a narrow strip or band approximately in thecenter of the wrap.

A further understanding of my invention will be had from the followingexamples which are set forth in order to illustrate preferredembodiments of my invention.

Example I In this example, an apparatus generally in accordance with thedisclosure of the attached drawing was used. A coating compositioncomprised of 4% cellulose acetate incorporated with 96%glycerol-triacetate (triacetin), before filling container 8, was cooledto room temperature and the coating process of the present invention wascarried out at room temperature.

The paper to be coated on the inside surface was fed through the processand apparatus of the present invention at a rate so as to produceapproximately 1,000 mm. filter rods per minute. The tank containing thecoating dope was positioned approximately 3 feet above the paper. Theamount of dope flowing through the applicator nozzle onto the paper wascontrolled by the amount of pressure between the nozzle and the paper.This can be done, as may be'seen from FIG. 2, by causing the paper tobreak or angle over the end of the nozzle after it goes over roll 25. Ifdesired, the applicator nozzle 21 may be positioned in a manner so thatthe vertical movement thereof against the paper can be controlled 'by ascrew adjustment or comparable means.

A relatively uniform level of coating composition was maintained in thesupply tank to insure a constant feed onto the paper and thus to providea relatively uniform coating. In general, this coating may beapproximately as thin as the apparatus will deposit continuously at thespeed of the paper moving under the nozzle. A coating of a thickness ofthe order of 0.008 inch up to 0.0012 inch is satisfactory. As will befurther noted from FIG. 2, the coating need not be applied to the edgeof the paper when it is desired to leave a margin for receiving sealingadhesive or glue when the paper has been positioned around the filterand the seam sealed. In this particular example the width of the nozzleused was approximately 4 mm. narrower than the 28 mm. width papertreated. The coating Went onto the paper very smoothly, and there was noaccumulation or clogging of the applicator nozzle or the forminggarniture when the paper proceeded to garniture 12 of FIG. 1.

Example I] A 2.1 denier per filament, 46,000 total denier, regularcross-section, 16 crimps per inch (c.p.i.) tow was wrapped in plug wrappaper after coating on one side with a 0.0005 coating of 85% Epolene Clow melting polyethylene and Piccolyte S-llSL (a polyterpene resin addedto improve the sealing). An apparatus substantially as pictured in thedrawing of the instant invention and described above was used to applythe coating composition. and to wrap the filter elements. The smokecould not by-pass in this filter.

Example III A 1.8 denier per filament, 41,000 total denier, regularcross-section, 2O c.p.i. tow was wrapped in a paper of 40 pound weightentirely coated on one side of the paper with a water-soluble animalglue. Again apparatus substantially the same as that pictured anddescribed elsewhere in the present application was used for applying thecoating composition to the paper and for wrapping the filaments with thepaper. The water-activated coating also formed the seam seal, and, aftera two hour curing time, the filaments of the filter rod were firmlyattached to the paper all the way around the filter by the glue.

Several different rods were made by the present invention usingrelatively fine denier filaments on the one hand to coarser filamentsfor other rods. These filter rods were compared with comparable filterrods made without the coating procedure of the present invention. Theresults of these comparisons are set forth in Table I which follows:

filament sizes are up to and include, for example, 16 denier perfilament. However, in general it appears that the present inventionprovides more advantage when used in conjunction with the finer denierfilaments of the order of 3 denier per filament or lower. In connectionwith filters made with these finer filaments, there may be some greatertendency of shrinkage to occur and use of the apparatus of the presentinvention overcomes any reduction of efficiency that could be caused bysuch shrinkage causing the filaments to pull away from the wrapper.

The cellulose acetate used above in the case of theplasticizer-sensitive coating composition had an acetyl content withinthe range of 38.5-40% and an intrinsic viscosity of about 1.Approximately l-1.5 grams of solution will satisfactorily coat 180 cm.length of the wrap. However, 2 parts of cellulose acetate of the sameacetyl content but of an intrinsic viscosity of 1.5-2 dissolved in 98parts of triacetin will give a good bond from about .51.0 gram ofsolution per 180 cm. of wrap.

Although I prefer the apparatus described above, since the applicatorshown constitutes a relatively simple and inexpensive way of adaptingexisting filter manufacturing equipment to the present invention, in thebroader aspects the present invention is not restricted exactly to theconstruction shown. It would be possible to replace :or supplement myapplicator construction with a wick or brush or to use a rollapplicator. Or, in certain instances special spray gun equipment couldbe substituted for my simple nozzle applicator. However, certain ofthese additional constructions would involve increased expense and wouldnot produce a better product. In the event added refinements are to bemade in the present apparatus, I would prefer to provide screwadjustment devices whereby my nozzle applicator might be better alignedand positioned vertically with respect to the rapidly moving paper.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be elfected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

I claim:

1. In a filter-making apparatus comprising, a filterforming garniture,means for feeding a strip of filter :wrap paper into said garniturealong a predetermined path, means for feeding cellulose acetatefilter-forming filaments into said garniture to be enwrapped therein bysaid strip, and means for applying a coating to said strip before it isfed into said garniture, the improvement wherein said filter wrap paperis further characterized by having a thickness of less than 0.06millimeter and said coating contains a plasticizer for celluloseacetate; and said coating applying means comprises an applicator havinga slot for apply- TABLE I With Coating Without Coating Filaments(D/F/TD) Rod Tip Percent Rod Tip Percent Pressure Pressure Percent TarRetrieval Pressure Pressure Percent Tar Removal (in. H2O) (in. H O)Removal Per in. Tip (in. H2O) (in. 11 0) Removal Per in. Tip

Pressure Pressure It will be observed from a consideration of the dateappearing in the above table, that, for example, a filter made using anapparatus substantially as described herein from fine-denier filamentsexhibits a removal of the order of 46.8 as compared with a comparablefilter produced Without the use of coating apparatus and wherein nocoating composition was applied, which had a removal of only 41.3.

Although in the above table the use of filament size up to 4 denier perfilament has been set forth, wrapper may be coated using the apparatusof the present invention and used to wrap continuous filamentousmaterial wherein the ing said coating to said strip, strip supportingmeans for guiding said strip as it moves in said path, and meanssupporting said applicator in contact adjacent said slot with saidstrip, at a position downstream of said strip supporting means, saidstrip being deflected from said path by said contact, whereby a uniform,continuous coating is applied at high speeds to said strip withouttearing it, and filaments, which contact the coated strip, are bonded toit in said garniture.

2. In a filter-making apparatus comprising, a filterforming garniture,means for feeding a strip of filter wrap paper into said garniture alonga predetermined path,

means for feeding filaments into said garniture to be enwrapped thereinby said strip, and means for applying a coating to said strip before itis fed into said garniture, the improvement wherein said filter wrappaper is further characterized by having a thickness of less than 0.06millimeters; and said means for applying a coating to said stripcomprises an applicator having a slot for applying said coating to saidstrip, strip supporting means for guiding said strip as it moves in saidpath, and means supporting said applicator in contact adjacent said slotwith said strip at a position downstream of said strip supporting means,said strip being deflected from said path by said contact, whereby auniform, continuous coating is applied at high speeds to said stripwithout tearing it.

3. The invention of claim 2 further characterized in that said stripsupporting means includes a roll on which the strip is guided as itmoves in said path; said slot is positioned transversely of said strip;and said applicator contact tends to wrap said strip further around saidroll.

4. In a filter-making apparatus comprising, a filterforming garniture,means for feeding a strip of wrapping material into said garniture alonga predetermined path, means for feeding filaments into said garniture tobe enwvrapped therein by said strip, and means for applying a coating tosaid strip before it is fed into said garniture, the improvement whereinsaid applying means comprises: an applicator having a slot for applyingsaid coating to said strip, strip supporting means for guiding saidstrip as it moves in said path, and means supporting said applicator incontact adjacent said slot with said strip, at a position downstream ofsaid strip supporting means, said strip be- (3 0 ing deflected from saidpath by said contact, whereby a uniform, continuous coating is appliedto said strip.

5. In a filter-making apparatus comprising, a filterforming garniture,means for feeding a strip of wrapping material into said garniture alonga predetermined path, means for feeding filaments into said garniture tobe enwrapped therein by said strip, and means for applying a coating tosaid strip before it is fed into said garniture, the improvement whereinsaid applying means comprises: an applicator having a slot for applyingsaid coating to said strip, said slot being positioned transversely ofsaid strip; and means supporting said applicator in contact adjacentsaid slot with said strip, and supporting means including aroll on whichsaid strip is guided as it moves in said path, said contact being at aposition in said path downstream of said roll so that said contactdeflects said strip and tends to wrap said strip further around theroll, whereby a uniform, continuous coating is applied to said strip.

References Cited by the Examiner 30 EARL M. BERGERT, Primary Examiner.

R. J. CARLSON, R. H. CRISS, Assistant Examiners.

1. IN A FILTER-MAKING APPARTUS COMPRISING, A FILTERFORMING GARNITURE,MEANS FOR FEEDING A STRIP OF FILTER WRAP PAPER INTO SAID GARNITURE ALONGA PREDETERMINED PATH, MEANS FOR FEEDING CELLULOSE ACETATE FILTER-FORMINGFILAMENTS INTO SAID GARNITURE TO BE ENWRAPPED THEREIN BY SAID STRIP, ANDMEANS FOR APPLYING A COATING TO SAID STRIP BEFORE IT IS FED INTO SAIDGARNITURE, THE IMPROVEMENT WHEREIN SAID FILTER WRAP PAPER IS FURTHERCHARACTERIZED BY HAVING A THICKNESS OF LESS THAN 0.06 MILLIMETER ANDSAID COATING CONTAINS A PLASTICIZER FOR CELLULOSE ACETATE; AND SAIDCOATING APPLYING MEANS COMPRISES AN APPLICATOR HAVING A SLOT FORAPPLYING SAID COATING TO SAID STRIP, STRIP SUPPOTING MEANS FOR GUIDINGSAID STRIP AS IT MOVES IN SAID PATH, AND MEANS SUPPORTING SAIDAPPLICATOR IN CONTACT ADJACENT SAID SLOT WITH SAID STRIP, AT A POSITIONDOWNSTREAM OF SAID STRIP SUPPORTING MEANS, SAID STRIP BEING DEFECTEDFROM SAID PATH BY SAID CONTACT, WHEREBY A UNIFORM, CONTINUSOU COATING ISAPPLIED AT HIGH SPEEDS TO SAID STRIP WITHOUT TEARING IT, AND FILAMENTS,WHICH CONTACT THE COATED STRIP, ARE BONDED TO IT IN SAID GARNITURE.